The APs "mark down" UP values to match the recommended Cisco AVVID values. So, UP 6 would be marked down to CoS 5. For H-REAP, the 802.1p value on the WLC is only used for downstream traffic. In your example, if the value was "6," then a CoS 5 packet would be sent with UP 6. If it was marked to "5," then the packet would be sent with UP 5.
As for trusting DSCP or CoS on the WLC port, you are correct that the WLC will mark both values on packets. However, if you trust DSCP, then any CoS-DSCP mappings that may be required would not be applied. Jason Boyers - CCIE #26024 (Wireless) Technical Instructor - IPexpert, Inc. Mailto: *[email protected] * On Fri, Apr 22, 2011 at 10:39 AM, Yuri Mecca <[email protected]> wrote: > Hi Jason, > > Thanks for the replies. > > About the question 5, lets clarify! When I say local mode, this mean "local > switching", not central. So, for that, if the SSID is Platinium with COS tag > 6 in WLC port, so the H-REAP will reply this tag? If I sniff the packets in > the H-REAP AP I will see tag 6, follow the WLC config? Of course, only if > the WMM client ask for Voice Queue. > > Another doubt, just in case that the lab asks to trust only dscp. I know > that the WLC marks CoS and DSCP, so technicaly theres no problem to trust > DSCP in the Controller Port, right? > > I didn't know that "mls qos" in global mode create this srr config in > interface level! Thats amazing... Less one thing to memorize! :-) > > Thanks again, thats really good points! > > Best regards, > > Yuri Mecca > > ------------------------------ > Date: Fri, 22 Apr 2011 10:25:15 -0400 > Subject: Re: [OSL | CCIE_Wireless] Wired and Wireless QoS > From: [email protected] > To: [email protected] > CC: [email protected] > > > My responses are inline below. And, everyone has doubts about QoS :) > > > Jason Boyers - CCIE #26024 (Wireless) > Technical Instructor - IPexpert, Inc. > Mailto: *[email protected] > * > > > On Wed, Apr 20, 2011 at 12:56 PM, Yuri Mecca <[email protected]> wrote: > > Hi Group, > > I'm studying to my exam and I found some doubts about QoS: > > 1) "End to End Qos" mean only trust the marked DSCP in AP port and COS in > Trunk / WLC ports and add at global config level "mls qos"? Or I need to > change the queues in global mode like auto-qos command? For voice > interfaces, I need to issue the "priority-queue out", SRR Shape and Shared > for compliance with the Voice best practices? > > *** "End to End QoS" would involve applying appropriate trusts on the > required switchports, which would depend on the situation. Local mode APs > would normally trust DSCP (which is not what auto qos would apply.) WLC > trunk ports should trust CoS. When you configure "mls qos," it > automatically configures SRR for all switchports on the 3560 switch. All 4 > output queues are given a value of 25 for sharing, while queue 1 is given a > value of 25 for shaping. I would only change these values if the > requirements state that one (or more) of the queues need to have a different > weight assigned to the queue. You should normally configure the > "priority-queue out" command on any interface which could have voice traffic > (marked with CoS 5) passing through it. When you configure that command, > CoS 5 traffic (by default) is serviced before anything else, up to 1/25 of > the bandwidth of the interface. It's "1/25" because the default shaping > value is 25. If you needed more than 4% for that traffic, you would need to > adjust the shaping value. > > > 2) In the autonomous AP I can setup Admission Control per SSID level. In > WLC I just see this option in the Voice or Video Parameter. This mean that > any SSID will use Admission Control or only ssid with WMM + Platinium/Gold > will use? > > *** This can be a bit confusing. When ACM is enabled, it applies to any > frames using the specified access category. So, if you configure Voice, > then any frames using UP 6 or 7 must make an ADDTS request in order to be > allowed. If the SSID uses Platinum and the client makes an ADDTS for UP 6, > the traffic would be allowed. If the SSID uses Gold and the client makes an > ADDTS for UP 6, the traffic would not pass. This is because only frames up > to UP 5 are allowed. If ACM had not been configured, the frame would have > been remarked to UP 5. > > > 3) If a client don't have WMM it will falls in the BE queue or BK queue? > > *** It uses the BE queue. > > > 4) If a client don't use TSPEC ADDTS it will falls in what queue? > > *** That depends on the UP value of the frame. If it has a UP value that > requires ACM, it will be blocked. If it has a UP value that does not > require ACM, it will use whatever queue applies to the UP value, up to the > maximum access category allowed by the SSID. In other words, if Voice CAC > is enabled and Video is not, then a frame with UP 5 using a WLAN with > Platinum or Gold would use the Video queue. If the WLAN used Silver, it > would use the BE queue. > > > 5) I know that in H-REAP the AP the AP marks follow WMM queue, but in the > Local mode, it follow the DSCP table based in the WMM too? > > *** I'm not quite sure what you are asking here, but I'll try to decipher > it. Please correct me. Local mode APs mark outgoing wired packets with a > DSCP value based on the received WMM value (for WMM clients.) H-REAP APs > mark outgoing wired packets with a CoS value based on the received WMM value > (for locally switched WMM clients.) There are many more variables in there, > but that's a start. > > > Thats all today! > > Best regards, > > Yuri Mecca > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > Are you a CCNP or CCIE and looking for a job? Check out > www.PlatinumPlacement.com <http://www.platinumplacement.com/> > > >
_______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com
